EN ISO 12957-1:2018

SLOVENSKI STANDARD
01-marec-2019
1DGRPHãþD
SIST EN ISO 12957-1:2005
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,62
Geosynthetics - Determination of friction characteristics - Part 1: Direct shear test (ISO
12957-1:2018)
Geokunststoffe - Bestimmung der Reibungseigenschaften - Teil 1: Scherkastenversuch
(ISO 12957-1:2018)
Géosynthétiques - Détermination des caractéristiques de frottement - Partie 1: Essai de
cisaillement direct (ISO 12957-1:2018)
Ta slovenski standard je istoveten z: EN ISO 12957-1:2018
ICS:
59.080.70 Geotekstilije Geotextiles
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 12957-1
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 59.080.70 Supersedes EN ISO 12957-1:2005
English Version
Geosynthetics - Determination of friction characteristics -
Part 1: Direct shear test (ISO 12957-1:2018)
Géosynthétiques - Détermination des caractéristiques Geokunststoffe - Bestimmung der
de frottement - Partie 1: Essai de cisaillement direct Reibungseigenschaften - Teil 1: Scherkastenversuch
(ISO 12957-1:2018) (ISO 12957-1:2018)
This European Standard was approved by CEN on 8 December 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12957-1:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 12957-1:2018) has been prepared by Technical Committee ISO/TC 221
"Geosynthetics" in collaboration with Technical Committee CEN/TC 189 “Geosynthetics” the secretariat
of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2019, and conflicting national standards shall be
withdrawn at the latest by June 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 12957-1:2005.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 12957-1:2018 has been approved by CEN as EN ISO 12957-1:2018 without any
modification.
INTERNATIONAL ISO
STANDARD 12957-1
Second edition
2018-12
Geosynthetics — Determination of
friction characteristics —
Part 1:
Direct shear test
Géosynthétiques — Détermination des caractéristiques de
frottement —
Partie 1: Essai de cisaillement direct
Reference number
ISO 12957-1:2018(E)
©
ISO 2018
ISO 12957-1:2018(E)
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 12957-1:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Principle . 3
5 Test specimens. 3
5.1 Sampling . 3
5.2 Number and dimensions of test specimens . 3
6 Conditioning . 3
7 Apparatus . 4
8 Procedure. 8
9 Calculations. 9
10 Test report .10
Bibliography .12
ISO 12957-1:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 221, Geosynthetics.
This second edition cancels and replaces the first edition (ISO 12957-1:2005), which has been technically
revised. The main changes compared to the previous edition are as follows:
— introduction of the possibility to test the shear between two geosynthetics;
— introduction of the possibility to test soil different from the standard sand.
A list of all parts in the ISO 12957 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 12957-1:2018(E)
Geosynthetics — Determination of friction
characteristics —
Part 1:
Direct shear test
1 Scope
This document specifies an index test method to determine the friction characteristics of geosynthetics
in contact with a standard sand as described in EN 196-1, i.e. with a specified density and moisture
content, under a normal stress and at a constant rate of displacement, using a direct shear apparatus.
The same testing procedure can be used with any type of soil with the density and moisture content
that are required to evaluate the performance under specific conditions or with another geosynthetic
under a normal stress and at a constant rate of displacement, using a direct shear apparatus.
The procedure can also be used for testing geosynthetic barriers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 9862, Geosynthetics — Sampling and preparation of test specimens
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
relative displacement
s
displacement of the sand, soil or other geosynthetic relative to the specimen during shearing
Note 1 to entry: Relative displacement is expressed in millimetres (mm).
3.2
normal force
N
constant vertical force applied to the specimen
Note 1 to entry: Normal force is expressed in kilonewtons (kN).
ISO 12957-1:2018(E)
3.3
shear force
S
horizontal force measured during shearing at a constant rate of displacement
Note 1 to entry: Shear force is expressed in kilonewtons (kN).
3.4
normal stress
σ
normal force (3.2) divided by the contact area of the specimen
Note 1 to entry: Normal stress is expressed in kilopascals (kPa).
3.5
shear stress
τ
shear force (3.3) along the sand, soil or other geosynthetic /geosynthetic interface, divided by the
contact area of the specimen
Note 1 to entry: Shear stress is expressed in kilopascals (kPa).
3.6
maximum shear stress
τ
max
maximum value of shear stress (3.5) developed in a shear test
Note 1 to entry: Maximum shear stress is expressed in kilopascals (kPa).
3.7
angle of friction
ϕ
slope of the "best fit regression straight line", through the plot of maximum shear stress (3.6)
Note 1 to entry: The angle of friction is expressed in degrees (°).
Note 2 to entry: In this document, ϕ is used to refer to the angle of friction between geosynthetic and sand, or
sg
geosynthetics and specific soil, and ϕ is used for the angle of friction between geosynthetic and geosynthetic.
gg
3.8
apparent cohesion
c
sg
calculated value of the shear stress (3.5) on the "best fit regression straight line" corresponding to zero
normal stress (3.4)
Note 1 to entry: Apparent cohesion is expressed in kilopascals (kPa).
Note 2 to entry: This term is used between geosynthetic and sand, or geosynthetics and specific soil.
3.9
maximum shear stress in sand or soil alone
τ
max,s
maximum shear stress (3.6) developed during a shear test on sand or soil alone
Note 1 to entry: Maximum shear stress in sand or soil alone is expressed in kilopascals (kPa).
2 © ISO 2018 – All rights reserved

ISO 12957-1:2018(E)
3.10
maximum shear stress sand or soil/support
τ
max,sup
maximum shear stress (3.6) developed during the shearing along the sand or soil/support interface
without geosynthetic
Note 1 to entry: Maximum shear stress sand or soil/support is expressed in kilopascals (kPa).
3.11
friction ratio
f (σ)
g
ratio of the maximum shear stress, τ (3.6) to the maximum shear stress in sand or soil alone, τ
max max,s
(3.9) for the same normal stress (3.4) σ
3.12
apparent adhesion
a
gg
calculated value of the shear stress (3.5) on the "best fit regression straight line" corresponding to zero
normal stress (3.4)
Note 1 to entry: Apparent adhesion is expressed in kilopascals (kPa).
Note 2 to entry: This term is used between geosynthet
...